UNIX for Dummies Questions & Answers

Hi, I have a large number of files which are numbered numerically, i.e. of the type

Code:

1.usr, 2.usr, 3.usr ...

This is what I'd like to do:

1. In ascending order, use awk to read a value from each file.

2. Write this value to another file (say data.txt). This file, 'data.txt' should be appended.

The problem is when I use the following command

Code:

awk '{print $2 }' *.usr > data.txt

It does write out all the data I need into a file but awk doesn't arrange the files in ascending order when it does it.

Thanks!

Code:

ls *.usr | xargs awk '{print $2 }' > data.txt

Don't blame awk. It's your shell doing the globbing in lexicographical order.

One way:

Code:

printf "%s\n" *.usr|sort -n|xargs awk '...'

Thanks!

Supposing that you have 1-3 digit user numbers, you could also use:

Code:

awk '{print $2 }' ?.usr ??.usr ???.usr > data.txt

without needing to resort to sort and xargs. Obviously, you'll need more terms in the list of files passed to awk if some of your *.usr names contain more than 3 digits; but the pattern should be obvious with this example.